Save the orangutans

Orangutans are in trouble. They are facing extinction and are in great danger. At OrangAid+, you'll learn more about these fascinating and unique relatives of human beings, and find out more about how to help.

Did you know orangutans are endangered and could go extinct?

Wild orangutans live only in Borneo and the Sumatra islands in Indonesia and Malaysia. (Fossils have also been found in mainland Asia throughout all of Southeast Asia, including Beijing, Taiwan, Myanmar, Laos, Thailand, Cambodia, the Malaysia Peninsula, and in Java.)

Orangutans share 98% of the genetic material with humans. They branched off from the hominoid line (the common ancestor of humans and apes) about 8-12 million years ago. Gibbons, gorillas, and chimpanzees (and bonobos) split from the hominid line about 17 million years ago, 8 million years ago, and 5-6 million years ago, respectively.

What can you do to help?

Orangutan FAQ

Where do orangutans live?

Wild orangutans live only in Borneo and the Sumatra islands in Indonesia and Malaysia. (Fossils have also been found in mainland Asia throughout all of Southeast Asia, including Beijing, Taiwan, Myanmar, Laos, Thailand, Cambodia, the Malaysia Peninsula, and in Java.)

How close are orangutans to humans?

Orangutans share 98% of the genetic material with humans. They branched off from the hominoid line (the common ancestor of humans and apes) about 8-12 million years ago. Gibbons, gorillas, and chimpanzees (and bonobos) split from the hominid line about 17 million years ago, 8 million years ago, and 5-6 million years ago, respectively.

Are orangs similar to humans?

Orangutans have many similar characteristics to humans. For example, females have a long period of pregnancy (8.5 months). Also, young orangutans have a long period of dependence, which is the second only to humans. Unlike chimpanzees, they show neither genital swelling during periods of sexual receptivity nor knuckle walking. They touch the ground with the palm of the hand while moving like human infants.

What is the scientific name for orangutans?

Orangutans have two subspecies: Pongo pygmaeus (the Bornean orangutan) and Pongo abelii (the Sumatran orangutan). Orangutans belong to family Pongidae (great apes).

What do they look like?

Orangutans have bright reddish brown hair. They are the largest tree-living mammals in the world. Their bodies are well adapted for arboreal life (tree-dwelling), while they are quite agile on the ground. They have long arms and fingers, and their feet can grip like hands. Their shoulder and hip joints have great mobility, and legs can be moved at almost all angles. Orangutans are sexually dimophic and males are much bigger than females (see below).

What do female and male orangutans look like?

Females grow up to 1 m and weigh up to 40 kg.

Males grow up to 1.5 m in height and weigh up to 120 kg! (Therefore, males more often travel on the ground than females.) They start to develop cheek pads and a throat pouch or sac when they become sexually mature. Cheek pads grow slowly and may continue to develop after sexual maturity is reached. It is known that the presence of dominant cheek-pad males inhibits the younger adult males’ development of their pads. The throat sac is used for making a very loud “long call”.

At which age do orangutans become mature?

Orangutans usually reach puberty at about 8 years of age, and start to reproduce when they are about 15 years old.

How long do orangutans live?

Their life span is typically 35 to 40 years in the wild, but they can sometimes live into their 50’s in captivity.

At which age do females start to have babies?

Females have their first offspring when they are 13-16 years old in the wild.

How often do females have babies?

Their birth interval is about 8 years, which is longer than gorillas’ 4-5 years and chimpanzees’ 6 years. They have an extremely low reproductive rate. Females at best raise four offspring in their lifetime and often just two. Their menstrual cycle is 29-32 days.

How dependent are infants?

Orangutans stay with their mother until they are about 7-8 years old. They may “leave home” when they are about 8-9 years old. Infants are dependant on their mother especially in the first 5 years of their lives, and form a strong bond with their mothers.

What do they eat?

Orangutans eat 400 different kinds of food that consists of fruits (e.g., figs and durians), plants of various kinds (e.g., leaves, bark, flowers, vines and nuts), honey, insects, and occasionally the meat of mammals and even soil!

Where do they sleep?

Orangutans make nests high up on trees every night to sleep.

How intelligent are they?

Orangutans are highly intelligent animals. They seem to remember where fruiting trees are located (spatial memory) and when the fruit will ripen (temporal memory). They are also known to be sophisticated tool users. For example, they chew leaves to make a sponge to soak up water in tree cavities, use big leaves for an umbrella, use branches as tools during insect foraging, honey collection, as protection against bees, to fish for branches or fruits, as a simple tool to scratch themselves, and drape large leaves over themselves like a poncho and so on. They also show great skills in cognitive tasks such as imitation, causal understanding, and inhibition in the laboratory.

How sociable are orangutans?

Orangutans are relatively solitary compared with other apes. They do not form large social groups or family groups. Adult males are usually alone, while adult females are accompanied by offspring.

What kind of social group do they form?

Four different kinds of social groups have been observed in the wild. The first consists of a mother and her offspring. The second is a consorting pair that is temporary and lasts a brief period. The third type of group is a traveling band, which is a small group moving and eating together. The forth is a temporary group observed at a fruiting tree (such as fig trees). The last two types of groups may include unrelated animals as group members.

What kind of factor decides the type of social group?

The type of social group seems to depend upon habitat, that is, availability of food and kind of forest. For example, in the upland and mountainous areas of Borneo, each adult male has a larger territory that overlaps with smaller territories of individual females. In the swamp forest in Sumatra, on the other hand, orangutans seem to be more social and up to 10 adults may feed in the same tree. Traveling bonds are also observed in this area.

What are threats for orangutans?

How many orangutans are left in the wild? Estimated number of orangutans in the wild was 315,000 in 1900, 80,000 in 1980s, and 20,000 in mid-1990s. The current number is thought to be much less than that. Some researchers estimate it 14,000, while others say 15,000-25,000. Either way, wild orangutans are at the risk of extinction. Bornean orangutans are endangered, while Sumatran orangutans are critically endangered. Some researchers believe that orangutans are disappearing at the rate of over 2,000 individuals a year!

What are threats for orangutans?

The main threat for orangutans is habitat loss. Their home of rainforest has been cut down for timber and pulp for paper. The forests are also cleared for palm oil plantations and gold mines. Orangutans are protected by laws in Indonesia and Malaysia as well as internationally, but illegal logging, mining, farming, and palm oil plantations are still continuing. Forest fires are another cause of habitat loss. In addition, infants are often captured for the illegal pet trade. Many of them die after the removal from their mothers due to shock. Their mothers are typically killed upon the capture of infants. Orangutans may be also killed for their meat or skulls. Various diseases such as Hepatitis B can threaten their lives as well.

Photos

Videos

Orangutans are very smart! They perform well in various kinds of cognitive tests such as quantitative judgment, spatial memory, and problem solving. For instance, when presented with two different amounts of food (5 vs. 3 pieces of monkey chow), they can reliably choose the larger reward. When a food is hidden in one of several identical opaque cups, they can successfully choose the correct cup even after a long delay. They are also creative and good at coming up with innovative solutions to novel problems. In a recent study, orangutans were given a clear tube that was vertically attached onto the cage mesh. Inside the tube was a peanut shell which was floating on water and out of their reach. How did the orangutans solve this problem? They got mouthfuls of water from a nearby dispenser and spat it into the tube until they could get the peanut!

Here, you can see a juvenile female orangutan and an adult male orangutan taking part in a cognitive test. The orangutans are presented with a pair of identical clear cups which are filled with different amounts of grape juice. They almost always choose the larger quantity because they love juice and they want more. After their first choice, the experimenter transfers the contents into a new pair of containers, which results in various kinds of transformations. Can they track the larger quantity after this modification? In other words, do orangutans understand that a liquid quantity remains the same even after it changes its appearance? This ability is called Piagetian liquid conservation, and human children understand this sometime around 7-8 years of age.

Here are some videos showing original research into orangutan's cognitive abilities:

Orangutan juice test # 1

An orangutan successfully tracks the larger of two quantities of grape juice after the liquid changes its appearance.

Orangutan juice test # 2

A male orangutan changes his mind during the test in which he is supposed to track the larger of two quantities of grape juice.

Orangutan Foundation International
A worldwide network dedicated to saving orangutans, with chapters in the UK, Australia and Indonesia and field reps in various countries. Their main operations are in Central Kalimantan but they support orangutan research and survival in other areas as well, including Sumatra, Malaysia, and the United States.

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About us

OrangAid+ is dedicated to educating the public about the plight of this extraordinary relative of ours. OrangAid+ is bilingual (English and Japanese) in order to spread the word to more people around the world.